1. Field of the Invention
The present invention relates to underground storage tank systems and to an improved method for installing a product monitoring device in such a tank with minimum disruption to the existing storage tank installation.
2. Description of the Prior Art
Underground storage tank systems are commonly employed for the storage of petroleum, hazardous chemicals and other products. For instance, most gasoline service stations, truck stops and similar facilities employ underground fuel storage tanks which are refilled by means of a riser pipe which extends upwardly from the buried tank into a relatively shallow manhole in the concrete apron of the location. The sides of the manhole are spaced a sufficient radial distance from the riser pipe to provide convenient access for coupling and uncoupling the supply hose of a supply truck to the top of the riser pipe. A fill tube extends within the riser pipe into the interior of the tank and is spaced concentrically within the riser pipe to thereby define an annular space between the fill tube and the riser pipe. The bottom of the manhole can be open or closed, e.g., cemented or filled with dirt or a mixture of pea gravel.
It is often advantageous to install a product monitoring device within the interior of the underground storage tank, e.g., to report product levels for inventory control purposes, or in special operating modes to detect tank leakage.
The present invention has as its object to provide a simple and economical method for installing a product monitoring device in an underground storage tank.
The present invention also has as its object to provide an improved installation method for such a device in an underground storage tank which allows minimum disruption to the existing storage tank installation, including the existing concrete apron which covers the buried storage tank.
Additional objects, features and advantages will be apparent in the written description which follows.